MUI, Power Icons, and a background pic - that won't eat too much chip mem. If you run in 8 or more colours there's some nice background pics in the /pix/back area of Aminet there's a good selection (my favourite is 'Esprit' which is 8 colours, but in 800x600 so probably not much use to you).
there's also Birdie, and ... erm ... that other one I don't use, that can add more eye candy to a basic Workbench.
